Construction method for replacing bridge with road under condition of unbalanced excavation and filling of cable-stayed bridge area

Abstract

The invention discloses a construction method for replacing a bridge with a road under the condition of unbalanced excavation and filling of a cable-stayed bridge area, relates to the field of construction, and selects a joint point of the road and the bridge by considering factors such as terrain, stress condition, construction convenience and feasibility of subsequent maintenance. After the steps of detailed geological investigation and measurement, geological drilling and testing, foundation treatment, construction of a connecting structure and pavement and bridge deck pavement are carried out, construction of the combination point is completed, pile foundation construction is carried out according to conditions, the problem that the combination point of the bridge and the pavement is affected by foundation settlement is solved, the bearing capacity and stability of the cable-stayed bridge are guaranteed, and the construction period is shortened. In combination with a way of replacing a bridge with a road, the construction of the road and the bridge can be completed within a short time by utilizing the rapidity and flexibility of road construction, a convenient traffic condition is provided for the construction of the cable-stayed bridge, and the construction efficiency is improved at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of construction, and in particular to a construction method of replacing a bridge with a road under the condition of unbalanced excavation and filling in a cable-stayed bridge area. Background Art

[0002] As an important form of bridge structure, cable-stayed bridge plays a key role in modern transportation construction. However, the construction process of cable-stayed bridge is complicated and faces many technical challenges. Among them, the imbalance of excavation and filling increases the difficulty of construction. In this case, the construction strategy of replacing bridge with road came into being and became an effective way to solve the construction difficulties of cable-stayed bridge. Replacing bridge with road can not only improve construction efficiency, but also reduce project costs, while ensuring construction quality and safety.

[0003] However, in the existing technology, roads have a large bearing capacity and good stability, which can provide a solid foundation for cable-stayed bridges; bridges have the characteristics of strong spanning capacity and beautiful appearance, which can meet traffic needs and landscape requirements. The selection of the junction between roads and bridges can give full play to the respective advantages of roads and bridges. However, in the existing construction methods, when the excavation and filling in the cable-stayed bridge area are unbalanced, the foundation settlement problem and pile foundation construction become difficulties in the construction process of replacing bridges with roads, which affects the stability of the junction between roads and bridges and poses certain safety risks. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method of replacing a bridge with a road under the condition of unbalanced excavation and filling in the cable-stayed bridge area, so as to solve the problems raised by the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a construction method of replacing a bridge with a road under the condition of unbalanced excavation and filling in the cable-stayed bridge area, comprising the following steps:

[0006] S1. Determination of the junction point between road construction and bridge: The junction point is selected according to the selection principle. After survey, test, foundation treatment, construction of connecting structure and paving of road surface and bridge deck, the construction of the junction point is completed, including:

[0007] S11. Conduct detailed geological surveys and measurements, and use advanced surveying instruments and technologies to accurately determine the location and topographic features of the junction points, and provide accurate data support for subsequent construction. For example, total stations, GPS and other surveying equipment can be used to accurately measure the coordinates, elevation and other parameters of the junction points;

[0008] S12. Conduct geological drilling and testing to understand the geological conditions and soil characteristics at the junction and take corresponding basic treatment measures;

[0009] S13, carry out foundation treatment, according to the geological survey results, the foundation at the joint point is reinforced and treated, the geological conditions are poor, the pile foundation method is used to improve the bearing capacity and stability of the foundation, and on the soft soil foundation, high-pressure jet grouting piles are used to reinforce the foundation;

[0010] S14. Carry out the construction of the connection structure. The connection structure is the key part of the connection between the road and the bridge. Reliable connection methods and high-strength materials should be used. The road and the bridge are firmly connected by combining reinforced concrete connection beams and steel box beam structures. During the construction process, the dimensional accuracy and installation quality of the connection structure must be ensured to ensure the tightness and stability of the connection;

[0011] S15. Pave the road and bridge deck. After the connection structure is completed, pave the road and bridge deck to ensure the stability and comfort of driving. Paving materials should be of reliable quality and good durability, such as asphalt concrete, cement concrete, etc. At the same time, pay attention to the flatness and slope control of the pavement to meet the driving safety and drainage requirements;

[0012] S2. Main beam construction: Main beam construction is carried out based on the bracket method;

[0013] S3. Cable-stayed cable construction: The cable-stayed cables are laid, tensioned and grouted, and the construction is completed after testing and timely processing.

[0014] Preferably, in step S14, the construction steps of combining the reinforced concrete connecting beam and the steel box beam structure include:

[0015] C1. Fabrication of steel box girders: Fabrication of steel box girders according to design drawings;

[0016] C2. Use cranes and other equipment to hoist the steel box girder onto the bottom piles formed by the pile foundation method or the high-pressure jet grouting method for installation;

[0017] C3. Carry out anti-corrosion treatment on the steel box girder;

[0018] C4. Cast reinforced concrete connecting beams on the steel box girder.

[0019] Preferably, the pile foundation method specifically comprises the following steps:

[0020] A1. Level the site, prepare materials and mechanical equipment;

[0021] A2. Pile position setting: According to the design drawings, use surveying instruments to set out the pile positions at the construction site, determine the location of the pile foundation, and set up obvious signs at the pile positions, such as wooden piles, steel bar heads, etc., to facilitate positioning and inspection during the construction process;

[0022] A3. Bury the casing. According to the pile diameter and geological conditions, select the appropriate casing material and specifications, dig a casing pit at the pile location, bury the casing in the pit, and check the position and verticality of the casing;

[0023] A4. Put the drilling rig in place. According to the type of pile foundation and construction requirements, select the appropriate drilling rig type and specifications, move the drilling rig to the pile position, adjust the position and verticality of the drilling rig, ensure that the drill bit center of the drilling rig coincides with the pile position center, and the verticality of the drilling rig meets the requirements;

[0024] A5. Start the drilling rig and drill holes according to the drilling parameters required by the design. During the drilling process, pay attention to controlling the drilling speed, mud density and other parameters to ensure the smooth progress of the drilling process;

[0025] A6. Hole cleaning: Use mud circulation method or slag extraction method to clean the hole and remove the mud and sediment in the hole. After the hole cleaning is completed, check the mud performance in the hole and the thickness of the sediment at the bottom of the hole to ensure that the mud performance meets the requirements and the thickness of the sediment at the bottom of the hole does not exceed the design requirements;

[0026] A7. Fabrication and installation of steel cage: According to the design requirements, fabricate the steel cage and install it into the hole using a crane. The installation of the steel cage must ensure that the position is accurate and the verticality meets the requirements;

[0027] A8. Concrete pouring: According to the design requirements, select the appropriate concrete mix ratio and slump, and use the conduit method to pour concrete. When the concrete is poured to the designed elevation, stop pouring and pull out the conduit;

[0028] A9. Pile head treatment: After the concrete pouring is completed, the excess concrete on the pile head shall be chiseled off to expose the steel bars, and the pile head shall be cleaned and maintained.

[0029] Preferably, the high-pressure jet grouting pile method specifically comprises the following steps:

[0030] B1. Construction preparation and pile position setting out;

[0031] B2. Put the drilling rig in place, move the high-pressure jet grouting pile driver to the pile position, adjust the position and verticality of the pile driver, and ensure that the drill bit center of the pile driver coincides with the center of the pile position;

[0032] B3. Start the high-pressure jet pile machine and make the drill bit drill downward while rotating. When the drill bit drills to the designed depth, stop drilling and record the drilling depth.

[0033] B4. Prepare cement slurry. Use a mixer to prepare cement slurry while drilling. The mix ratio of cement slurry should be determined according to the design requirements. Generally, the water-cement ratio of cement slurry is 0.8-1.5. The prepared cement slurry should have good fluidity and stability to meet the requirements of high-pressure jet grouting pile construction;

[0034] B5, high-pressure rotary jet grouting, the prepared cement slurry is transported into the drill pipe through a high-pressure pump, and then sprayed out from the nozzle of the drill bit. Under the action of high pressure, the cement slurry is injected into the soil in a high-speed jet manner, fully mixed with the soil, and formed a cement-soil pile body;

[0035] B6. Lift the drill pipe. When the cement slurry is injected to a certain depth, start lifting the drill pipe and perform high-pressure jet grouting while lifting until the drill pipe is lifted to the ground.

[0036] B7. After cleaning the equipment, test the pile strength, diameter and integrity.

[0037] Preferably, the selection principle includes:

[0038] Terrain: Choose areas with relatively flat terrain and stable geological conditions as the connection points to ensure the stability of the connection between the road and the bridge. For example, when constructing in mountainous areas, you can choose areas with a small mountain slope and a relatively stable rock layer to avoid setting connection points in areas prone to geological disasters such as landslides and mud-rock flows;

[0039] Stress conditions: The connection point should be located at a reasonable position between the bridge and the road to evenly transfer the load. For example, for a cable-stayed bridge, the connection point can be selected at a relatively small position of the main beam, avoiding connection in areas with large bending moments and shear forces to reduce adverse effects on the bridge structure;

[0040] Construction and subsequent maintenance: Consider the entry of construction equipment, transportation of materials and subsequent maintenance.

[0041] Preferably, the construction of the main beam specifically includes:

[0042] D1. Carry out the construction of the support foundation: according to the geological conditions at the joint point and the load requirements of the main beam, select the appropriate support foundation form, expand the foundation and pile foundation, excavate, treat and pour the foundation to ensure the bearing capacity and stability of the foundation. For example, on a soft soil foundation, cement mixing piles can be used to reinforce the foundation to improve the bearing capacity of the foundation;

[0043] D2. Erection of the scaffolding: According to the shape, size and construction requirements of the main beam, select the appropriate type of scaffolding, full-height scaffolding or beam-column scaffolding. The scaffolding should be erected strictly in accordance with the design requirements to ensure the strength, rigidity and stability of the scaffolding. For example, a steel pipe scaffolding can be used to erect a full-height scaffolding. The spacing, step length and dimensions of the crossbars and vertical poles of the scaffolding can be determined by calculation to ensure that the scaffolding can bear the weight of the main beam and the construction load;

[0044] D3. Install the formwork: The formwork should have sufficient strength, rigidity and sealing to ensure the dimensional accuracy and appearance quality of the main beam. The formwork should be installed firmly and reliably to avoid deformation and leakage during concrete pouring. For example, steel formwork or wooden formwork can be used for installation, customized according to the shape and size of the main beam, and ensure that the connection between the formwork and the bracket is firm;

[0045] D4. Tie the steel bars and lay the prestressed pipes: The specifications, quantity and arrangement of the steel bars should meet the design requirements. The steel bars should be tied firmly and reliably to avoid loosening and displacement during the concrete pouring process. The laying of the prestressed pipes should be carried out strictly in accordance with the design requirements to ensure that the pipes are positioned accurately and unobstructed. For example, corrugated pipes can be used as prestressed pipes, which can be laid after the steel bars are tied, and the pipes can be fixed to the steel skeleton by positioning the steel bars;

[0046] D5. Concrete pouring and curing: The concrete mix ratio should be determined according to the design requirements and construction conditions to ensure the strength and durability of the concrete. Concrete pouring should be carried out continuously to avoid cold joints and stratification. After the concrete pouring is completed, timely curing should be carried out to ensure the strength and appearance quality of the concrete. For example, watering curing, covering with plastic film and other methods can be used for curing, and the curing time should be no less than 7 days.

[0047] Preferably, the method of laying out the stay cable specifically includes:

[0048] E1. Select appropriate cable specifications and models according to design requirements. Before laying the cables, check the cables to ensure they are free of damage, rust and other quality issues;

[0049] E2. Use a dedicated cable-releasing device to release the cable: Use dedicated equipment to slowly release the cable from the cable drum. Pay attention to controlling the cable-releasing speed to avoid the cable from being twisted, bent, or damaged due to excessive speed. At the same time, arrange for a dedicated person to observe and monitor the cable to promptly discover and handle possible problems.

[0050] Preferably, the cable tensioning and grouting specifically include:

[0051] F1. Determine the tensioning sequence and tensioning force of the cable according to the design requirements: The tensioning of the cable should be carried out symmetrically from the middle to both ends, and the tensioning force should be gradually increased to avoid tensioning in place at one time. During the tensioning process, professional tensioning equipment, such as jacks, oil pressure gauges, etc., should be used, and the operation should be carried out strictly in accordance with the operating procedures. For example, it is necessary to ensure that the connection between the jack and the cable is firm and reliable, and the reading of the oil pressure gauge is accurate, etc.;

[0052] F2. Monitor the elongation of the cable to ensure that it is within the design allowable range. If the elongation exceeds the allowable range, stop tensioning in time, analyze the cause and take appropriate measures to adjust;

[0053] F3. Clean the pipeline of the inclined cable to ensure that there is no debris or water in the pipeline;

[0054] F4. Use special grouting equipment to inject cement slurry into the pipeline. During the grouting process, the grouting pressure and speed must be controlled to ensure that the cement slurry can fully fill the pipeline;

[0055] F5. Check the grouting quality to ensure that it is dense and has no voids. For example, ultrasonic testing and other methods can be used to test the grouting quality and any problems found can be dealt with in a timely manner.

[0056] Preferably, the cable-releasing device comprises a layer frame, a stepping motor, a worm gear box, a cable drum member and a cross frame, the output end of the worm gear box is drivingly connected with a transmission shaft, the cable drum member is rotatably mounted on the outer ring surface of the transmission shaft, a convex tooth is provided in the middle of the transmission shaft, a reduction mechanism is slidably engaged with the outer side of the convex tooth, the reduction mechanism comprises a rocker, a side frame, a rubber block, a mounting frame and a collar, a groove is provided on the inner side of the collar, the groove is engaged with the convex tooth, an annular groove is provided on the outer ring of the collar, the end of the rocker is clamped on the inner wall of the annular groove, the side frame and the mounting frame are both rotatably connected to the middle part of the rocker, the shafts of the side frame and the rocker are provided with torsion springs, and a convex block on one side of the cable drum member is staggered and engaged with a convex block on one side of the collar.

[0057] Preferably, the rubber block is fixedly connected to one end of the side frame, the rubber block abuts against the outer side of the cable disc, the mounting frame is fixedly connected to one side of the worm gear box by bolts, the worm gear box and the cross frame are both fixedly connected to the inside of the layer frame, the other end of the transmission shaft is rotatably connected to the middle part of the cross frame, and the stepping motor is fixedly mounted on the input end of the worm gear box.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] 1. In the present invention, the junction of the road and the bridge is selected by considering factors such as the terrain, stress conditions, construction convenience and feasibility of subsequent maintenance. After detailed geological survey and measurement, geological drilling and testing, foundation treatment, construction of the connection structure and paving steps of the road surface and the bridge deck, the construction of the junction is completed. The problem of the junction of the bridge and the road surface being affected by the foundation settlement is solved by carrying out pile foundation construction according to different situations, so as to ensure the bearing capacity and stability of the cable-stayed bridge. In combination with the method of replacing the bridge with the road, the rapidity and flexibility of the road construction can be utilized to complete the construction of the road and the bridge in a shorter time, thereby providing convenient traffic conditions for the construction of the cable-stayed bridge and improving the construction efficiency.

[0060] 2. In the present invention, when the cable release speed is too fast, the rocker is held and moved in the direction of the cable drum, and the rocker moves in a fan shape around the connection point with the mounting frame. The protrusion at the other end of the rocker applies force to the collar through the annular groove, so that the collar moves toward the worm gear box on the surface of the transmission shaft. At this time, the groove and the convex tooth are disengaged, resulting in the collar protrusion and the protrusion at the end of the cable drum being disengaged, and the cable drum is no longer subjected to torque. At the same time, when the rocker approaches the cable drum, it will fit and push the side frame, and the side frame will fit the edge of the cable drum with the help of the rubber block. Under the action of friction, the cable drum gradually slows down, thereby slowing down the cable release speed, achieving the purpose of effectively controlling the cable release speed without turning off the motor, and avoiding damage to the motor by repeated starting and stopping. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of the three-dimensional structure of a cable-laying device in a construction method of replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area according to the present invention;

[0062] Figure 2 It is a schematic diagram of a partial three-dimensional structure of a cable-laying device in a construction method of replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area according to the present invention;

[0063] Figure 3 It is a partially exploded three-dimensional structural schematic diagram of a cable-laying device in a construction method of replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area according to the present invention;

[0064] Figure 4 It is a three-dimensional structural schematic diagram of a speed reduction mechanism in a construction method of replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area according to the present invention.

[0065] In the figure: 1. shelf; 2. stepper motor; 3. worm gear box; 31. transmission shaft; 32. convex teeth; 4. reduction mechanism; 41. rocker; 42. side frame; 43. rubber block; 44. mounting frame; 45. collar; 46. groove; 47. ring groove; 5. cable drum piece; 6. cross frame. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Embodiment 1: A construction method for replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area, comprising the following steps:

[0068] S1. Determination of the junction point between road construction and bridge: The junction point is selected according to the selection principle. After survey, test, foundation treatment, construction of connecting structure and paving of road surface and bridge deck, the construction of the junction point is completed, including:

[0069] S11. Conduct detailed geological surveys and measurements, and use advanced surveying instruments and technologies to accurately determine the location and topographic features of the junction points, and provide accurate data support for subsequent construction. For example, total stations, GPS and other surveying equipment can be used to accurately measure the coordinates, elevation and other parameters of the junction points;

[0070] S12. Conduct geological drilling and testing to understand the geological conditions and soil characteristics at the junction and take corresponding basic treatment measures;

[0071] S13, carry out foundation treatment, according to the geological survey results, the foundation at the joint point is reinforced and treated, the geological conditions are poor, the pile foundation method is used to improve the bearing capacity and stability of the foundation, and on the soft soil foundation, high-pressure jet grouting piles are used to reinforce the foundation;

[0072] The specific steps of pile foundation method include:

[0073] A1. Level the site, prepare materials and mechanical equipment;

[0074] A2. Pile position setting: According to the design drawings, use surveying instruments to set out the pile positions at the construction site, determine the location of the pile foundation, and set up obvious signs at the pile positions, such as wooden piles, steel bar heads, etc., to facilitate positioning and inspection during the construction process;

[0075] A3. Bury the casing. According to the pile diameter and geological conditions, select the appropriate casing material and specifications, dig a casing pit at the pile location, bury the casing in the pit, and check the position and verticality of the casing;

[0076] A4. Put the drilling rig in place. According to the type of pile foundation and construction requirements, select the appropriate drilling rig type and specifications, move the drilling rig to the pile position, adjust the position and verticality of the drilling rig, ensure that the drill bit center of the drilling rig coincides with the pile position center, and the verticality of the drilling rig meets the requirements;

[0077] A5. Start the drilling rig and drill holes according to the drilling parameters required by the design. During the drilling process, pay attention to controlling the drilling speed, mud density and other parameters to ensure the smooth progress of the drilling process;

[0078] A6. Hole cleaning: Use mud circulation method or slag extraction method to clean the hole and remove the mud and sediment in the hole. After the hole cleaning is completed, check the mud performance in the hole and the thickness of the sediment at the bottom of the hole to ensure that the mud performance meets the requirements and the thickness of the sediment at the bottom of the hole does not exceed the design requirements;

[0079] A7. Fabrication and installation of steel cage: According to the design requirements, fabricate the steel cage and install it into the hole using a crane. The installation of the steel cage must ensure that the position is accurate and the verticality meets the requirements;

[0080] A8. Concrete pouring: According to the design requirements, select the appropriate concrete mix ratio and slump, and use the conduit method to pour concrete. When the concrete is poured to the designed elevation, stop pouring and pull out the conduit;

[0081] A9. Pile head treatment: After the concrete pouring is completed, the excess concrete on the pile head shall be chiseled off to expose the steel bars, and the pile head shall be cleaned and maintained.

[0082] The specific steps of high pressure jet grouting pile method include:

[0083] B1. Construction preparation and pile position setting out;

[0084] B2. Put the drilling rig in place, move the high-pressure jet grouting pile driver to the pile position, adjust the position and verticality of the pile driver, and ensure that the drill bit center of the pile driver coincides with the center of the pile position;

[0085] B3. Start the high-pressure jet pile machine and make the drill bit drill downward while rotating. When the drill bit drills to the designed depth, stop drilling and record the drilling depth.

[0086] B4. Prepare cement slurry. Use a mixer to prepare cement slurry while drilling. The mix ratio of cement slurry should be determined according to the design requirements. Generally, the water-cement ratio of cement slurry is 0.8-1.5. The prepared cement slurry should have good fluidity and stability to meet the requirements of high-pressure jet grouting pile construction;

[0087] B5, high-pressure rotary jet grouting, the prepared cement slurry is transported into the drill pipe through a high-pressure pump, and then sprayed out from the nozzle of the drill bit. Under the action of high pressure, the cement slurry is injected into the soil in a high-speed jet manner, fully mixed with the soil, and formed a cement-soil pile body;

[0088] B6. Lift the drill pipe. When the cement slurry is injected to a certain depth, start lifting the drill pipe and perform high-pressure jet grouting while lifting until the drill pipe is lifted to the ground.

[0089] B7. After cleaning the equipment, test the pile strength, diameter and integrity;

[0090] S14. Carry out the construction of the connection structure. The connection structure is the key part of the connection between the road and the bridge. Reliable connection methods and high-strength materials should be used. The road and the bridge are firmly connected by combining reinforced concrete connection beams and steel box beam structures. During the construction process, the dimensional accuracy and installation quality of the connection structure must be ensured to ensure the tightness and stability of the connection;

[0091] Specifically, the construction steps of the combination of reinforced concrete connecting beam and steel box beam structure include:

[0092] C1. Fabrication of steel box girders: Fabrication of steel box girders according to design drawings;

[0093] C2. Use cranes and other equipment to hoist the steel box girder onto the bottom piles formed by the pile foundation method or the high-pressure jet grouting method for installation;

[0094] C3. Carry out anti-corrosion treatment on the steel box girder;

[0095] C4. Cast reinforced concrete connecting beams on the steel box girder.

[0096] S15. Pave the road and bridge deck. After the connection structure is completed, pave the road and bridge deck to ensure the stability and comfort of driving. Paving materials should be of reliable quality and good durability, such as asphalt concrete, cement concrete, etc. At the same time, pay attention to the flatness and slope control of the pavement to meet the driving safety and drainage requirements;

[0097] The selection principles include:

[0098] Terrain: Choose areas with relatively flat terrain and stable geological conditions as the connection points to ensure the stability of the connection between the road and the bridge. For example, when constructing in mountainous areas, you can choose areas with a small mountain slope and a relatively stable rock layer to avoid setting connection points in areas prone to geological disasters such as landslides and mud-rock flows;

[0099] Stress conditions: The connection point should be located at a reasonable position between the bridge and the road to evenly transfer the load. For example, for a cable-stayed bridge, the connection point can be selected at a relatively small position of the main beam, avoiding connection in areas with large bending moments and shear forces to reduce adverse effects on the bridge structure;

[0100] Construction and subsequent maintenance: Consider the entry of construction equipment, transportation of materials and subsequent maintenance.

[0101] S2. Main beam construction: Main beam construction is carried out based on the bracket method;

[0102] The construction of the main beam specifically includes:

[0103] D1. Carry out the construction of the support foundation: according to the geological conditions at the joint point and the load requirements of the main beam, select the appropriate support foundation form, expand the foundation and pile foundation, excavate, treat and pour the foundation to ensure the bearing capacity and stability of the foundation. For example, on a soft soil foundation, cement mixing piles can be used to reinforce the foundation to improve the bearing capacity of the foundation;

[0104] D2. Erection of the scaffolding: According to the shape, size and construction requirements of the main beam, select the appropriate type of scaffolding, full-height scaffolding or beam-column scaffolding. The scaffolding should be erected strictly in accordance with the design requirements to ensure the strength, rigidity and stability of the scaffolding. For example, a steel pipe scaffolding can be used to erect a full-height scaffolding. The spacing, step length and dimensions of the crossbars and vertical poles of the scaffolding can be determined by calculation to ensure that the scaffolding can bear the weight of the main beam and the construction load;

[0105] D3. Install the formwork: The formwork should have sufficient strength, rigidity and sealing to ensure the dimensional accuracy and appearance quality of the main beam. The formwork should be installed firmly and reliably to avoid deformation and leakage during concrete pouring. For example, steel formwork or wooden formwork can be used for installation, customized according to the shape and size of the main beam, and ensure that the connection between the formwork and the bracket is firm;

[0106] D4. Tie the steel bars and lay the prestressed pipes: The specifications, quantity and arrangement of the steel bars should meet the design requirements. The steel bars should be tied firmly and reliably to avoid loosening and displacement during the concrete pouring process. The laying of the prestressed pipes should be carried out strictly in accordance with the design requirements to ensure that the pipes are positioned accurately and unobstructed. For example, corrugated pipes can be used as prestressed pipes, which can be laid after the steel bars are tied, and the pipes can be fixed to the steel skeleton by positioning the steel bars;

[0107] D5. Concrete pouring and curing: The concrete mix ratio should be determined according to the design requirements and construction conditions to ensure the strength and durability of the concrete. Concrete pouring should be carried out continuously to avoid cold joints and stratification. After the concrete pouring is completed, timely curing should be carried out to ensure the strength and appearance quality of the concrete. For example, watering curing, covering with plastic film and other methods can be used for curing, and the curing time should be no less than 7 days.

[0108] S3. Cable-stayed cable construction: The cable-stayed cables are laid, tensioned and grouted, and the construction is completed after testing and timely processing.

[0109] Furthermore, the laying of the stay cable specifically includes:

[0110] E1. Select appropriate cable specifications and models according to design requirements. Before laying the cables, check the cables to ensure they are free of damage, rust and other quality issues;

[0111] E2. Use a dedicated cable-releasing device to release the cable: Use dedicated equipment to slowly release the cable from the cable drum. Pay attention to controlling the cable-releasing speed to avoid the cable from being twisted, bent, or damaged due to excessive speed. At the same time, arrange for a dedicated person to observe and monitor the cable to promptly discover and handle possible problems.

[0112] Cable tensioning and grouting specifically include:

[0113] F1. Determine the tensioning sequence and tensioning force of the cable according to the design requirements: The tensioning of the cable should be carried out symmetrically from the middle to both ends, and the tensioning force should be gradually increased to avoid tensioning in place at one time. During the tensioning process, professional tensioning equipment, such as jacks, oil pressure gauges, etc., should be used, and the operation should be carried out strictly in accordance with the operating procedures. For example, it is necessary to ensure that the connection between the jack and the cable is firm and reliable, and the reading of the oil pressure gauge is accurate, etc.;

[0114] F2. Monitor the elongation of the cable to ensure that it is within the design allowable range. If the elongation exceeds the allowable range, stop tensioning in time, analyze the cause and take appropriate measures to adjust;

[0115] F3. Clean the pipeline of the inclined cable to ensure that there is no debris or water in the pipeline;

[0116] F4. Use special grouting equipment to inject cement slurry into the pipeline. During the grouting process, the grouting pressure and speed must be controlled to ensure that the cement slurry can fully fill the pipeline;

[0117] F5. Check the grouting quality to ensure that it is dense and has no voids. For example, ultrasonic testing and other methods can be used to test the grouting quality and any problems found can be dealt with in a timely manner.

[0118] Embodiment 2: According to Figure 1 - Figure 4As shown, the cable-releasing device includes a layer frame 1, a stepping motor 2, a worm gear box 3, a cable disc 5 and a cross frame 6. The output end of the worm gear box 3 is connected to a transmission shaft 31. The cable disc 5 is rotatably mounted on the outer ring surface of the transmission shaft 31. A convex tooth 32 is provided in the middle of the transmission shaft 31. A reduction mechanism 4 is slidably engaged with the outer side of the convex tooth 32. The reduction mechanism 4 includes a rocker 41, a side frame 42, a rubber block 43, a mounting frame 44 and a collar 45. A groove 46 is provided on the inner side of the collar 45. The groove 46 is engaged with the convex tooth 32. The outer ring of the collar 45 is provided with a ring groove 47. The end of the rocker 41 is engaged with the ring The inner wall of the groove 47, the side frame 42 and the mounting frame 44 are all rotatably connected to the middle part of the rocker 41, the shafts of the side frame 42 and the rocker 41 are provided with torsion springs, the protrusions on one side of the cable disc 5 are staggered and engaged with the protrusions on one side of the ring 45, the rubber block 43 is fixedly connected to one end of the side frame 42, the rubber block 43 abuts against the outer side of the cable disc 5, the mounting frame 44 is fixedly connected to one side of the worm gear box 3 by bolts, the worm gear box 3 and the cross frame 6 are both fixedly connected to the inside of the layer frame 1, the other end of the transmission shaft 31 is rotatably connected to the middle part of the cross frame 6, and the stepping motor 2 is fixedly installed at the input end of the worm gear box 3.

[0119] In this embodiment, the cable-releasing device is installed on a trailer. In the initial state, the cable drum 5 contains the inclined cable. In the cable-releasing stage, the stepper motor 2 is started, and the stepper motor 2 injects power into the worm gear box 3, which drives the transmission shaft 31 to rotate. In the initial state, the protrusion of the collar 45 and the protrusion at the end of the cable drum 5 are staggered and engaged. At this time, the convex teeth 32 and the groove 46 on the inner wall of the collar 45 are engaged. The rotation of the transmission shaft 31 will drive the collar 45 to rotate, and the end of the rocker 41 will rotate along the annular groove 47, which will not affect the normal rotation of the collar 45. Under the bite action of the protrusions of the collar 45 and the cable drum 5, the collar 45 drives the cable drum 5 to rotate to perform the cable-releasing operation. When the cable-releasing speed is too fast, the rocker 41 is held and moved in the direction of the cable drum 5, and the rocker 41 revolves around the connection with the mounting frame 44. The contact point moves in a fan shape, and the protrusion at the other end of the rocker 41 applies force to the collar 45 through the annular groove 47, so that the collar 45 moves toward the worm gear box 3 on the surface of the transmission shaft 31. At this time, the groove 46 and the convex tooth 32 are disengaged, resulting in the collar 45 protrusion and the end protrusion of the cable disc 5 being disengaged, and the cable disc 5 is no longer subjected to torque. At the same time, when the rocker 41 approaches the cable disc 5, it will fit and push the side frame 42. The side frame 42 sticks to the edge of the cable disc 5 with the help of the rubber block 43. Under the action of friction, the cable disc 5 gradually slows down, thereby slowing down the speed of releasing the cable, achieving the purpose of effectively controlling the speed of releasing the cable without turning off the motor, avoiding damage to the motor by repeated starting and stopping. After the rocker 41 is in the middle position, under the action of the torsion spring, the side frame 42 gradually returns to the initial position, and the rubber block 43 does not contact the cable disc 5.

[0120] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A construction method of replacing a bridge with a road under unbalanced excavation and filling conditions in a cable-stayed bridge area, characterized in that: The following steps are involved: S1. Determination of the junction point between road construction and bridge: The junction point is selected according to the selection principle. After survey, test, foundation treatment, construction of connecting structure and paving of road surface and bridge deck, the construction of the junction point is completed, including: S11. Conduct detailed geological surveys and measurements, using advanced surveying instruments and techniques to accurately determine the location of the junction and the topographic features; S12. Conduct geological drilling and testing to understand the geological conditions and soil characteristics at the junction and take corresponding basic treatment measures; S13, carry out foundation treatment, according to the geological survey results, the foundation at the joint point is reinforced and treated, the geological conditions are poor, the pile foundation method is adopted, and the foundation is reinforced on the soft soil foundation with high-pressure jet grouting piles; S14. Carry out the construction of the connection structure, using a combination of reinforced concrete connection beams and steel box beam structures to firmly connect the road and the bridge together; S15, paving the road and bridge deck; S2. Main beam construction: Main beam construction is carried out based on the bracket method; S3. Cable-stayed cable construction: The cable-stayed cables are laid, tensioned and grouted, and the construction is completed after testing and timely processing.

2. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: In step S14, the construction steps of the combination of reinforced concrete connecting beam and steel box beam structure include: C1. Fabrication of steel box girders: Fabrication of steel box girders according to design drawings; C2. Use cranes and other equipment to hoist the steel box girder onto the bottom piles formed by the pile foundation method or the high-pressure jet grouting method for installation; C3. Carry out anti-corrosion treatment on the steel box girder; C4. Cast reinforced concrete connecting beams on the steel box girder.

3. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The specific steps of the pile foundation method include: A1. Level the site, prepare materials and mechanical equipment; A2. Pile position setting: According to the design drawings, use surveying instruments to set out the pile positions at the construction site, determine the location of the pile foundation, and set up obvious signs at the pile positions; A3. Bury the casing. According to the pile diameter and geological conditions, select the appropriate casing material and specifications, dig a casing pit at the pile location, bury the casing in the pit, and check the position and verticality of the casing; A4. Drilling rig in place. According to the type of pile foundation and construction requirements, select the appropriate drilling rig type and specifications, move the drilling rig to the pile position, and adjust the position and verticality of the drilling rig; A5. Start the drilling rig and drill holes according to the drilling parameters required by the design; A6. Hole cleaning: Use mud circulation method or slag extraction method to clean the hole and remove the mud and sediment in the hole. After the hole cleaning is completed, check the mud performance in the hole and the thickness of the sediment at the bottom of the hole; A7. Fabrication and installation of steel cage: fabricate the steel cage according to the design requirements and install it into the hole using a crane; A8. Concrete pouring: According to the design requirements, select the appropriate concrete mix ratio and slump, and use the conduit method to pour concrete. When the concrete is poured to the designed elevation, stop pouring and pull out the conduit; A9. Pile head treatment: After the concrete pouring is completed, the excess concrete on the pile head shall be chiseled off to expose the steel bars, and the pile head shall be cleaned and maintained.

4. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The high-pressure jet grouting pile method specifically comprises the following steps: B1. Construction preparation and pile position setting out; B2. After the drilling rig is in place, move the high-pressure jet grouting machine to the pile position and adjust the position and verticality of the pile machine; B3. Start the high-pressure jet pile machine and make the drill bit drill downward while rotating. When the drill bit drills to the designed depth, stop drilling and record the drilling depth. B4. Prepare cement slurry. While drilling the hole, use a mixer to prepare cement slurry. B5, high-pressure rotary jet grouting, the prepared cement slurry is transported into the drill pipe through a high-pressure pump, and then sprayed out from the nozzle of the drill bit to form a cement soil pile body; B6. Lift the drill pipe. When the cement slurry is injected to a certain depth, start lifting the drill pipe and perform high-pressure jet grouting while lifting until the drill pipe is lifted to the ground. B7. After cleaning the equipment, test the pile strength, diameter and integrity.

5. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The selection principles include: Terrain: Choose an area with relatively flat terrain and stable geological conditions as the connection point. When constructing in mountainous areas, choose an area with a small mountain slope and a relatively stable rock layer; Stress conditions: Choose the part of the main beam where the stress is relatively small; Construction and subsequent maintenance: Consider the entry of construction equipment, transportation of materials and subsequent maintenance.

6. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The construction of the main beam specifically includes: D1. Carry out the construction of the support foundation: select the appropriate support foundation form according to the geological conditions at the joint point and the load requirements of the main beam; D2. Erection of the support: According to the shape, size and construction requirements of the main beam, select the appropriate support type, full-height support or beam-column support; D3. Install the formwork: Use steel formwork or wooden formwork for installation, and customize it according to the shape and size of the main beam; D4. Tie up the steel bars and lay the prestressed pipes: Use corrugated pipes as prestressed pipes, lay them after the steel bars are tied up, and fix the pipes on the steel skeleton by positioning the steel bars; D5. Carry out pouring and curing of concrete.

7. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The stay cable laying specifically includes: E1. Select appropriate cable specifications and models according to design requirements; E2. Use a dedicated cable-releasing device to release the cable: Use special equipment to slowly release the inclined cable from the cable drum.

8. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 1, characterized in that: The cable tensioning and grouting specifically include: F1. Determine the tensioning sequence and tensioning force of the inclined cables according to the design requirements: the tensioning of the inclined cables should be carried out symmetrically from the middle to both ends, and the tensioning force should be gradually increased to avoid tensioning in place at one time; F2. Monitor the elongation of the stay cable; F3. Clean the pipeline of the inclined cable to ensure that there is no debris or water in the pipeline; F4. Use special grouting equipment to inject cement slurry into the pipeline. During the grouting process, the grouting pressure and speed must be controlled; F5. Check the grouting quality by ultrasonic testing and other methods, and deal with any problems found in a timely manner.

9. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 7, characterized in that: The cable-releasing device comprises a layer frame (1), a stepping motor (2), a worm gear box (3), a cable disc (5) and a cross frame (6); the output end of the worm gear box (3) is drivingly connected to a transmission shaft (31); the cable disc (5) is rotatably mounted on the outer ring surface of the transmission shaft (31); a convex tooth (32) is provided in the middle of the transmission shaft (31); a speed reduction mechanism (4) is slidably engaged with the outer side of the convex tooth (32); the speed reduction mechanism (4) comprises a rocker (41), a side frame (42), a rubber block (43), a mounting frame (44) and a sleeve A ring (45) is provided with a groove (46) on the inner side of the ring (45), the groove (46) and the convex tooth (32) are engaged with each other, an annular groove (47) is provided on the outer ring of the ring (45), the end of the rocking arm (41) is engaged with the inner wall of the annular groove (47), the side frame (42) and the mounting frame (44) are both rotatably connected to the middle part of the rocking arm (41), the shafts of the side frame (42) and the rocking arm (41) are provided with torsion springs, and a protrusion on one side of the cable disc (5) is staggered and engaged with a protrusion on one side of the ring (45).

10. The method for constructing a cable-stayed bridge by replacing a road with a bridge under unbalanced excavation and filling conditions in the area of ​​the cable-stayed bridge according to claim 9, characterized in that: The rubber block (43) is fixedly connected to one end of the side frame (42), the rubber block (43) abuts against the outer side of the cable disc member (5), the mounting frame (44) is fixedly connected to one side of the worm gear box (3) by bolts, the worm gear box (3) and the cross frame (6) are both fixedly connected to the inside of the layer frame (1), the other end of the transmission shaft (31) is rotatably connected to the middle part of the cross frame (6), and the stepping motor (2) is fixedly mounted on the input end of the worm gear box (3).

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